A common-source amplifier providing both a high gain and high input impedance is an amplifier most frequently in use. However, when an input signal frequency becomes high, the gain of the common-source amplifier sharply decreases because of a Miller effect.
The Miller effect may be suppressed by a cross-coupled differential amplifier in which a pair of common-source amplifiers is cross-coupled by capacitors. (For example, refer to Japanese Laid-open Patent Publication No. 2006-521748.)
However, the cross-coupled differential amplifier has a problem of large power consumption because two common-source amplifiers are driven.